1. Field of the Invention
This invention relates to a bracket designed to support and to hold in a vertical position the sidewall of a trench used for laying pipe, conduit, electrical cable, etc. More specifically, this bracket comprises a three-piece unit which may be assembled to perform its supporting function. Still more specifically, this bracket comprises a base element and two vertical side elements which are fitted into and firmly held in a vertical position by the base element.
2. State of the Prior Art
Trenches for the described purpose are used presently such as described in U.S. Pat. No. 2,862,367. These comprise, in some cases, concrete slabs having dimensions of about 2".times.12".times.5' which are supported on precast concrete brackets which have a horizontal base and a vertical portion extending upward at a point about 3" from the end of the base. Two of these brackets are positioned with the horizontal bases abutting each other and the vertical portions in the furthest position from each other so that the aforementioned 3" portion of each bracket is in a position to support abutting, adjacent ends of two of the concrete slabs. These slabs serve as the sidewalls of the trench.
These precast concrete brackets are difficult to cast, heavy and difficult to transport and because of the 90.degree. angle in these brackets, there is considerable breakage even when steel reinforced.
Prior to the above type of trenches, cast iron linings were used such as shown in U.S. Pat. No. 1,805,435. These are obviously much more expensive.
Welded steel brackets have also been used in which horizontal and vertical channel steel pieces have been welded together to form one unit used for supporting the precast concrete sidewalls of a channel. These are awkward and heavy to transport.